Yes, the patterned jacket is traditional, but there's no reason it has to feel old-fashioned. Try one of these unexpected, distinctly modern approaches.

Classic, But Not Formal
When it comes in a slim, contemporary cut and bold (but not loud) colors, a plaid blazer can inject pizzazz into even the most pedestrian outfit. Just follow the example of this cotton-nylon jacket from Gucci. Frida Giannini designed it to evoke a modern-day gentleman's club, but you don't have to save it for a night out; slip it on anytime you want a look that's classic but not formal.